001    /**
002     * Copyright (c) 2000-2012 Liferay, Inc. All rights reserved.
003     *
004     * This library is free software; you can redistribute it and/or modify it under
005     * the terms of the GNU Lesser General Public License as published by the Free
006     * Software Foundation; either version 2.1 of the License, or (at your option)
007     * any later version.
008     *
009     * This library is distributed in the hope that it will be useful, but WITHOUT
010     * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
011     * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
012     * details.
013     */
014    
015    package com.liferay.portal.kernel.notifications;
016    
017    import java.util.Comparator;
018    
019    /**
020     * @author Edward Han
021     */
022    public class NotificationEventComparator
023            implements Comparator<NotificationEvent> {
024    
025            public NotificationEventComparator() {
026                    this(true);
027            }
028    
029            public NotificationEventComparator(boolean ascending) {
030                    _ascending = ascending;
031            }
032    
033            public int compare(
034                    NotificationEvent notificationEvent1,
035                    NotificationEvent notificationEvent2) {
036    
037                    if (notificationEvent1.equals(notificationEvent2)) {
038                            return 0;
039                    }
040    
041                    long value =
042                            notificationEvent1.getDeliverBy() -
043                                    notificationEvent2.getDeliverBy();
044    
045                    if (value == 0) {
046                            value =
047                                    notificationEvent1.getTimestamp() -
048                                            notificationEvent2.getTimestamp();
049                    }
050    
051                    if (value == 0) {
052                            value =
053                                    notificationEvent1.hashCode() - notificationEvent2.hashCode();
054                    }
055    
056                    if (_ascending) {
057                            return (int)value;
058                    }
059                    else {
060                            return (int)-value;
061                    }
062            }
063    
064            private boolean _ascending;
065    
066    }